In the psephological hullabaloo that followed the first TV Prime Ministerial debate, pundits began to pay particular attention to those voting "blocs" that might hold the balance of power.

As the three main parties jostle within a few percentage points of one another, every vote was said to count, which in reality meant that a few more votes in a few more marginal constituencies were now a bit more significant. In this wide open, three-horse race with everything to play for in the second half (choose your cliché), those groups who thought and voted as groups have become all the more important.

Theos research suggests that Catholics are slightly more inclined to consider themselves Labour, an allegiance that has a long and strong history according to British Social Attitudes surveys.

Church of England data are a bit more difficult to disentangle, as they tend to sweep up nominal Anglicans with practising ones. However, even with this bluntness, research shows that the long-standing bias of Anglicans towards the Conservative Party remains strong.

The "Other Christian" category, which means Nonconformists and newer, independent churches, shows little bias one way or another, which is not entirely surprising given how diverse this group is. Sample sizes for other religious groups are too small to be reliable.

So, there are some theo-political biases. Only the Muslim inclination towards Labour justifies the epithet "powerful" but beyond that religion still shapes political affiliation to some degree.

But so what? There are plenty of other influential factors and some of them, like age or social grade, are far better predictors of voting intention. Is religion that significant?

On one level it is not. Careless talk of election-shaping bloc votes is misleading. Religious votes will not decide this election any more than the youth or the C1 vote will.

There is, however, another trend in the religious data that is worth noting. According to BSA research, Christians (of any denomination) are "more likely to think of themselves as closer to one political party" than are people of "no religion". Similarly people of no religion are consistently less likely to claim they are "partisan" in their politics.

The Theos data cited above show that people in the "No religion" category are less likely to have voted in 2005 and, when asked in February, were less likely to vote this year than any other group except Muslims. They were also more likely than any other group except Muslims to respond "Don't know" when asked what party affiliation they "generally" had.

The lovely thing about these data is that they can be spun both ways. The religious person, or at least the Christian, will say something like "Research shows that we are actually committed to democracy. We get involved. We vote. We want to make things better and, contrary to what atheist polemicists claim, we do so through the democratic process."

By contrast, the non-religious person will say something like "Research shows we are free-thinkers. We don't toe the party line. We make up our minds for ourselves, rather than jumping on bandwagons. If we don't vote it is because we have judged that parties are not worth voting for."

Both lines of argument have something to recommend them, although the data give no idea as to whether it is independence of mind or sheer indifference that underlies the "no religion" disengagement.

Whichever line is more convincing, in the current political context it is those who are prepared to engage who will make a difference. There is no religious "bloc" vote but there is evidence that, perhaps because they are accustomed to belonging to a wider social group, religious people will exercise a disproportionate impact on this election.